A 25-year-old Levin woman died when she was thrown from the vehicle in a crash late last night.
Levin Senior Sergeant Sam Gilpin said the woman was the only person in the car, which crashed on State Highway 57, between Shannon and Levin.
"It's too early to say whether [she] was wearing a seatbelt," he said.
"I can confirm the occupant was ejected [from the car]."
Gilpin said no one else was in the car, despite reports of a baby seat being in it.
"A truck was involved and is being examined by the Serious Crash Unit.
"It wasn't involved in the initial crash and became involved afterwards."